Irrelevant speech in classrooms and road traffic noise adjacent to schools have a substantial impact on children's ability to learn. Comparing the effects of different noise sources on learning may help construct guidelines for noise abatement programs. Experimental studies are important to establish dose-response relationships and to expand our knowledge beyond correlation studies. This experiment examined effects of road traffic noise and irrelevant speech on children's reading speed, reading comprehension, basic mathematics, and mathematical reasoning. A total of 187 pupils (89 girls and 98 boys), 12-13 years old, were tested in their ordinary classrooms. Road traffic noise was found to impair reading speed (P &lt; 0.01) and basic mathematics (P &lt; 0.05). No effect was found on reading comprehension or on mathematical reasoning. Irrelevant speech did not disrupt performance on any task. These findings are related to previous research on noise in schools and the implications for noise abatement guidelines are discussed.

This paper reports two experiments on the effects of degraded speech signals on memory for spoken lectures. Experiment 1 showed that broadband noise impairs university students’ memory for a spoken lecture, even though the participants heard what was said. Experiment 2 showed that reverberation has detrimental effects to school adolescents’ memory for spoken lectures, similar to broadband noise. The results suggest that poor listening conditions (resulting from background noise and/or long reverberation time) impair memory and learning, even if the conditions allow the listeners to hear what is said. Since the goal for students and pupils attending to lectures is to remember the lecture rather than just hearing what is said, the results presented here indicate that standards for acceptable signal-to-noise ratios and reverberation times in buildings designed for learning should consider the distinction between speech intelligibility and memory. Standards should be based on memory criteria instead of intelligibility criteria.

The aim of this investigation was to study the biases and accuracy in age estimation of persons selling alcohol. Two experiments are reported, both suggesting that the accuracy in age estimation of Swedish alcohol salespersons is higher than that of control persons. This expertise in age estimation is probably the result of the extensive training Swedish alcohol salespersons go through as a natural part of their profession. Nonetheless, their estimates were not free from bias. Salespersons overestimated the age of target persons below 20 years of age and thus too young to buy alcohol. The results also revealed that controls, in contrast to salespersons, assimilated their estimates towards their own age (i.e. an own-anchor effect). Furthermore, female participants were shown to estimate the age of old target persons (56-65 years) more accurately than male participants. These results are discussed in relation to previous findings on training in age estimation and present jurisdiction.